Hole cutter with multiple fulcrums

ABSTRACT

A hole cutter has a cylindrical blade body including a cutting edge and one or more axially-elongated apertures formed within a side wall of the blade body. The axially-elongated aperture is configured to receive a lever, such as a screwdriver, therethrough. Each axially-elongated aperture includes a first fulcrum axially spaced adjacent to the cutting edge, a second fulcrum axially spaced further away from the cutting edge than the first fulcrum, and optionally a third fulcrum axially spaced between the first and second fulcrums. A lever, such as a screwdriver, can be inserted into the aperture and placed against each of the fulcrums to lever slugs out of the interior of the blade body.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of co-pending U.S. patent applicationSer. No. 14/708,596, filed on May 11, 2015, titled “Hole Cutter withMultiple Fulcrums”, which is a continuation of U.S. patent applicationSer. No. 29/496,442, filed Jul. 14, 2014, titled “Hole Saw”, which is adivisional of U.S. patent application Ser. No. 29/465,441, filed Aug.28, 2013, now U.S. Pat. No. D711,441, issued Aug. 19, 2014, titled “HoleSaw,” which is a divisional of U.S. patent application Ser. No.29/417,810, filed Apr. 9, 2012, now U.S. Pat. No. D692,470, issued Oct.29, 2013, titled “Hole Saw”, which is a continuation of the followingapplications: U.S. patent application Ser. No. 29/353,762, filed Jan.13, 2010, now U.S. Pat. No. D690,334, issued Sep. 24, 2013, titled “HoleSaw”; U.S. patent application Ser. No. 29/353,759, filed Jan. 13, 2010,now U.S. Pat. No. D659,176, issued May 8, 2012, titled “Hole Saw”; U.S.patent application Ser. No. 13/006,117, filed Jan. 13, 2011, titled“Hole Cutter with Chip Egress Aperture,” which is a continuation-in-partof U.S. patent application Ser. No. 12/687,078, filed Jan. 13, 2010,titled “Hole Cutter with Chip Egress Aperture”; and U.S. patentapplication Ser. No. 13/006,080, filed Jan. 13, 2011, now U.S. Pat. No.8,579,555, issued Nov. 12, 2013, titled “Hole Cutter withAxially-Elongated Aperture Defining Multiple Fulcrums”, which is acontinuation-in-part of U.S. patent application Ser. No. 12/687,065filed Jan. 13, 2010, now U.S. Pat. No. 8,579,554, issued Nov. 12, 2013,titled “Hole Cutter with Axially-Elongated Aperture Defining MultipleFulcrums,” the entire contents of each of which are hereby expresslyincorporated herein by reference as part of this application for allpurposes.

FIELD OF THE INVENTION

The present invention relates to hole cutters, and more particularly, tohole cutters with apertures in their side walls that define fulcrums forinserting and levering a tool, such as a screwdriver, to remove workpiece slugs from the interiors of the hole cutters.

BACKGROUND

A hole cutter, or hole saw, is a type of cutter used in drillingcircular holes in various materials, such as wood, metal, drywall, etc.A hole cutter typically has a substantially cylindrical body thatdefines a side wall, a circular cutting edge with teeth located at oneend of the body and designed to cut a work piece during rotation of thecutter, and a cap located at the end of the body opposite the cuttingedge. The cap typically includes threads, holes or other structureadapted to allow the hole cutter to be drivingly connected to a drill,such as through an arbor. In use, the circular cutting edge creates acircular hole in a work piece and, in turn, removes a circular workpiece slug therefrom. Typically, after the hole is cut in the workpiece, the work piece slug is retained within the hollow interior of thehole cutter and must be removed therefrom prior to cutting another hole.

Prior art hole cutters include apertures or slots formed in the sidewalls of the hole cutters that allow users to insert a lever, such as ascrewdriver, through the side wall and into the interior of the holecutter to, in turn, lever or otherwise urge the slug out of the holecutter. This manual slug removal task can be time-consuming and takesubstantial effort on the part of the user. A slug may be difficult toextract from within the body of a cutter, even with a hole cutter thatincludes slug removal apertures or slots, because the slug can becometightly wedged in the cutter or because the slug removal apertures orslots are not aligned with the slug. For example, a slug may becomewarped or cracked and thus firmly lodged within the hole cutter. Asanother example, some work pieces, such as woods, contain sticky orglue-like residue that inhibits slug removal. As yet another example,thicker and thinner work pieces will create slugs of differingthicknesses and slugs positioned at different locations within the holecutter. A thick work piece can create a thick slug that is pushed deepinto the body of the hole cutter, whereas a thin work piece can create athin slug located near the cutting edge. Accordingly, slugs often do notsimply “pop” out of the cutter when worked by a tool. Slugs often slideshort distances, twist, tilt or otherwise gradually or incrementallymove along the inside of the cutter. The apertures in the side walls ofprior art hole cutters can be relatively short, and therefore may beused only to remove either relatively thin or relatively thick workpiece slugs, but not both types of slugs, and possibly not slugs ofmedium thicknesses. Other prior art hole cutters have plural aperturesthat are axially and angularly spaced relative to each other, whereineach aperture is relatively short in length. These types of aperturesmay require moving the screwdriver or other lever from one aperture toanother in order to lever a slug out of the hole cutter. Further, no oneaperture may be properly positioned for a particular slug thickness, ora particular slug positioning within the interior of the hole cutter,further contributing to the difficult and time consuming nature of theslug removal process.

Accordingly, it is an object of the present invention to overcome one ormore of the above-described drawbacks and/or disadvantages of the priorart.

SUMMARY OF THE INVENTION

In accordance with a first aspect, the present invention is directed toa hole cutter comprising a substantially cylindrical blade body defininga cutting edge and at least one axially-elongated aperture formedthrough the blade body. The axially-elongated aperture is configured toreceive therethrough a lever, such as a screwdriver, for removing a workpiece slug from the interior of the blade body. The blade body defineswithin the axially-elongated aperture a plurality of fulcrums forengaging the lever and levering slugs out of the interior of the bladebody. The fulcrums include a first fulcrum axially spaced adjacent tothe cutting edge and a second fulcrum axially spaced further away fromthe cutting edge than the first fulcrum. Some embodiments of the presentinvention further include a third fulcrum axially spaced between thefirst and second fulcrums.

In some embodiments of the present invention, such as for relativelylarge diameter hole cutters, the hole cutter comprises a plurality ofthe axially-elongated apertures angularly spaced relative to each other.In other embodiments of the present invention, such as for relativelysmall diameter hole cutters, the hole cutter comprises only oneaxially-elongated aperture. In some such embodiments, the relativelysmall diameter hole cutters have diameters of about 1 7/16 inch or less,and the relatively large diameter hole cutters have diameters of about 1½ inch or greater. In some such embodiments, the axially-elongatedaperture(s) is (are) oriented substantially parallel to the axis of thehole cutter for hole cutters having diameters of about 1 7/16 inch orless, and the axially-elongated apertures are oriented at an acute anglerelative to the axis of the hole cutter for hole cutters havingdiameters of about 1 ½ inch or greater.

In some embodiments of the present invention, the first fulcrum islocated at approximately one end of the axially-elongated aperture, andthe second fulcrum is located at approximately an opposite end of theaperture relative to the first fulcrum. In some embodiments, a thirdfulcrum is located approximately midway between the first and secondfulcrums.

In some embodiments of the present invention, the second fulcrum isangularly and axially spaced relative to the first fulcrum, and in someembodiments, a third fulcrum is angularly and axially spaced between thefirst and second fulcrums. The hole cutter defines a direction ofrotation that is the cutting direction of the cutting edge. In some suchembodiments, the axially-elongated aperture defines a first end axiallyspaced adjacent to the cutting edge, and a second end axially spacedfurther away from the cutting edge than the first end and angularlyspaced relative to the first end in a direction opposite to the cuttingdirection. In some such embodiments, the axially-elongated aperturedefines an axially-elongated slot oriented at an acute angle relative tothe axis of the blade body. The acute angle is at least about 30degrees, and preferably is within the range of about 35 degrees, toabout 60 degrees.

In some such embodiments, the first fulcrum is axially spaced from thecutting edge a first distance within the range of about ½ inch to about1 inch, the second fulcrum is angularly spaced relative to the firstfulcrum and is axially spaced from the cutting edge a second distancewithin the range of about 1 ½ to about 2 inches, and the third fulcrumis angularly and axially spaced between the first and second fulcrumsand is axially spaced from the cutting edge a third distance within therange of about 1 inch to about 1 ½ inches. In some embodiments of thepresent invention, the first distance of the first fulcrum is configuredfor levering slugs having thicknesses of about ½ inch or less, the thirddistance of the third fulcrum is configured for levering slugs havingthicknesses of about 1 inch or less, and the second distance of thesecond fulcrum is configured for levering slugs having thicknesses ofabout 1 ½ inches or less.

In some embodiments of the present invention, the axially-elongatedaperture defines a first end adjacent to the cutting edge, and the firstend is axially spaced from the cutting edge a first distance within therange of about 15/100 inch to about ⅜ inch. In some such embodiments,the cutting edge is defined by a plurality of saw teeth including tipsand gullets between the tips, and the first distance is measured fromeither (i) a deepest gullet of the cutting edge, or (ii) a planeextending between tips of unset teeth of the cutting edge.

In some embodiments of the present invention, each fulcrum is defined bya fulcrum surface oriented substantially parallel to the cutting edge.In some such embodiments, the fulcrum surface is rectilinear,curvilinear or both. In some such embodiments, the hole cutter includesa non-working end on the opposite end of the blade body relative to thecutting edge, and each fulcrum is formed on the edge of the respectiveaperture adjacent to, or on the side of, the non-working end of the holecutter. In some such embodiments, each of a plurality of fulcrumsdefines a recess in said edge of the respective aperture adjacent to, oron the side of, the non-working end of the hole cutter.

In accordance with another aspect, the present invention is directed toa hole cutter comprising a substantially cylindrical blade body defininga cutting edge and at least one axially-elongated aperture formedthrough the blade body. The axially-elongated aperture is configured toreceive therethrough a lever for removing work piece slugs from theinterior of the blade body. The blade body defines within theaxially-elongated aperture first means axially spaced adjacent to thecutting edge for engaging the lever and levering slugs havingthicknesses within a first range of thicknesses out of the blade bodyand second means axially spaced further away from the cutting edge thanthe first means for engaging the lever and levering slugs out of theblade body having thicknesses within a second range of thicknessesgreater than the first range of thicknesses. Some embodiments of thepresent invention further include third means axially spaced between thefirst and second means for engaging the lever and levering slugs out ofthe blade body having thicknesses within a range of thickness betweenthe first and second range of thicknesses.

In some embodiments of the present invention, each of the first, secondand third means is a respective fulcrum. In some embodiments of thepresent invention, the second means is angularly spaced relative to thefirst means, and the third means is angularly spaced between the firstand second means. In some such embodiments, the third means is axiallyand angularly spaced approximately midway between the first and secondmeans. In some embodiments, the at least one axially-elongated aperturedefines an axially-elongated slot.

In some such embodiments, the hole cutter defines a direction ofrotation that is the cutting direction of the cutting edge, and theaxially-elongated aperture defines a first end axially spaced adjacentto the cutting edge, and a second end axially spaced further away fromthe cutting edge than the first end and angularly spaced relative to thefirst end in a direction opposite the cutting direction. In some suchembodiments, the first means is axially spaced from the cutting edge afirst distance within the range of about ½ inch to about 1 inch, thesecond means is angularly spaced relative to the first means and isaxially spaced from the cutting edge a second distance within the rangeof about 1 ½ to about 2 inches, and the third means is angularly andaxially spaced between the first and second means and is axially spacedfrom the cutting edge a third distance within the range of about 1 inchto about 1 ½ inches. In some embodiments, the first means is forlevering slugs having thicknesses of less than about ½ inch, the thirdmeans is for levering slugs having thicknesses of less than about 1inch, and the second means is for levering slugs having thicknesses ofless than about 2 inches. Preferably, at least a portion of each of thefirst, second and third means is substantially parallel to the cuttingedge.

One advantage of the hole cutters of the present invention is that theycan provide a relatively quick, easy, and effective means to extractslugs from inside the hole cutters. Another advantage of the holecutters of the present invention is that they provide multiple fulcrumsat different axial locations, and in some embodiments, angularlocations, to facilitate aligning the fulcrums with a variety of workpiece slugs of different thicknesses. Yet another advantage of the holecutters of the present invention is that they provide multiple fulcrumswithin the same axially-elongated aperture and thereby allow a user towork a slug out of the cutter by using multiple fulcrums withoutremoving the lever, such as a screwdriver, from the aperture.

These and other advantages of the present invention, and/or of thecurrently preferred embodiments thereof, will become more readilyapparent in view of the following detailed description of currentlypreferred embodiments and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of a hole cutter blade of the presentinvention prior to being formed into a cylindrical blade body shape.

FIG. 2 is a perspective view of another embodiment of a hole cutterembodying the present invention.

FIG. 3 is a side elevational view of the blade of the hole cutter ofFIG. 2 prior to being formed into a cylindrical blade body shape.

FIG. 4 is a side elevational view of another embodiment of a hole cutterblade of the present invention used for smaller diameter hole cuttersand prior to being formed into a cylindrical blade body shape.

FIG. 5 is a side elevational view of another embodiment of a hole cutterblade of the present invention used for smaller diameter hole cuttersand prior to being formed into a cylindrical blade body shape.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

In FIG. 1, a blade body of a hole cutter embodying the present inventionis indicated generally by the reference numeral 10. The term “holecutter” is used here to mean a tool that cuts holes in work pieces, suchas wood or metal work pieces, and includes without limitation hole saws.The blade body 10 is shown in FIG. 1 in its flattened state; however, aswill be recognized by those of ordinary skill in the pertinent art basedon the teachings herein, the blade body 10 is rolled or otherwise formedinto a substantially cylindrical shape to form the hole cutter. Theblade body 10 comprises a side wall 12 that extends around an axis ofrotation “X” of the hole cutter to define a substantially cylindricalblade body. One end of the blade body is provided with a cutting edge 14oriented substantially perpendicular to the axis of rotation X, and theopposing end of the blade body defines a rim 16. A cap (not shown) isfixedly secured to the rim 16 to enclose the respective end of the holecutter. The end of the hole cutter opposite the cutting edge 14 andincluding the rim 16 and a cap (not shown) attached thereto is referredto herein as the “non-working” end of the hole cutter. As recognized bythose of ordinary skill in the pertinent art, the cap (not shown) mayinclude a threaded hub and pin apertures so that the hole cutter can becoupled to, and driven by, an arbor drivingly connected to a power tool,such as an electric drill. As shown in FIG. 1, the cutting edge 14 isdefined by a plurality of teeth with gullets extending between theteeth. However, as may be recognized by those of ordinary skill in thepertinent art based on the teachings herein, the cutting edge may bedefined by any of numerous different tooth forms or other cutting edgeforms that are currently known or that later become known. Similarly,although the blade body 10 is formed from sheet metal that is rolled orotherwise formed into the cylindrical blade body 10 of the hole cutterand is, in turn, welded or otherwise attached to a cap, the hole cuttermay be formed in any of numerous other ways that are currently known, orthat later become known. For example, the end cap and side wall 12 maybe spun, drawn, molded or otherwise formed in one part.

As shown in FIG. 1, the blade body 10 defines two axially-elongatedapertures or slots 18 formed through the side wall 12 thereof. As can beseen, the two slots 18 are angularly spaced relative to each other onthe cylindrical blade body 10. In the illustrated embodiment, the twoslots 18 are approximately equally spaced relative to each other, i.e.,the two slots are spaced about 180 degrees, relative to each other. Invarious embodiments of the invention, each slot 18 has an axial depth D5(D4−D2) ranging from about 1 ⅛ inches to about 1 ⅘ inches. In theillustrated embodiment, each slot 18 has an axial depth D5 of about 1 ⅓inches. In certain embodiments, each slot 18 has a circumferentiallength L ranging from about an inch to about 1 ⅘ inches. In theillustrated embodiment, each slot 18 has a circumferential length L ofabout 1 ⅕ inches. As described in further detail below, eachaxially-elongated aperture or slot 18 is configured to receivetherethrough a lever, such as a screwdriver, for removal of a work pieceslug located within the interior of the blade body 10.

The number of axially-elongated apertures or slots 18 formed through theside wall 12 of the hole cutter depends on the size of the hole cutter.As a general rule, the larger the diameter of the hole cutter, thegreater is the number of axially-elongated apertures or slots 18 thatcan be formed through the cylindrical blade body 10. In the currentlypreferred embodiments of the present invention, relatively smalldiameter hole cutters (e.g., about 9/16 inch diameter to about 1 3/16inch diameter) have one slot 18 oriented substantially parallel to theaxis X of the hole cutter, larger diameter hole cutters have two slots18 (e.g., about ⅞ inch diameter to about 1 7/16 inches diameter)oriented substantially parallel to the axis X of the hole cutter, stilllarger diameter hole cutters (e.g., about 1 ½ inches diameter to about 3⅜ inches diameter) have two larger area slots 18 that are oriented atacute angles relative to the axis X of the hole cutter, and still largerdiameter hole cutters (e.g., about 3 ½ inches diameter to about 6 inchesdiameter) have four larger area slots 18 oriented at acute anglesrelative to the axis X of the hole cutter. In the currently preferredembodiments of the hole cutters having multiple axially-extending slots18, the axially-extending slots 18 are approximately equally spacedrelative to each other about the axis X of the hole cutter, i.e., ifthere are two axially-extending slots 18 they are angularly spaced about180 degrees, relative to each other, if there are threeaxially-extending slots 18 they are angularly spaced about 120 degrees,relative to each other, if there are four axially-extending slots 18they are angularly spaced about 90 degrees, relative to each other, etc.However, as may be recognized by those of ordinary skill in thepertinent art based on the teachings herein, the axially-extendingapertures or slots 18 need not be equally spaced relative to each other,nor do all axially-elongated apertures or slots 18 on the same holecutter need to define the same aperture area or slot configuration.

In the illustrated embodiment, as shown in FIG. 1, eachaxially-elongated aperture or slot 18 includes three fulcrums 20A, 20Band 20C axially and angularly spaced relative to each other. However, asmay be recognized by those of ordinary skill in the pertinent art basedon the teachings herein, the slot 18 may include fewer than threefulcrums, or more than three fulcrums. The fulcrums 20A, 20B and 20C arerecessed edge surfaces of the side wall 12 of the blade body 10 that areformed on the edge of a respective axially-extending aperture or slot 18that is adjacent to, or on the side of, the non-working end of the holecutter. In the embodiment of FIG. 1, the fulcrums 20A, 20B and 20Cextend linearly in a direction substantially perpendicular to the axisof rotation X of the hole cutter or substantially parallel to thecutting edge 14. Accordingly, a common tool, such as a screwdriver, canbe inserted into the axially-extending aperture or slot 18, slipped intoengagement with a respective fulcrum 20A, 20B or 20C, and manipulated asa lever against the respective fulcrum 20A, 20B or 20C to pry or push aslug out of the interior of the blade body 10. Each fulcrum 20A, 20B and20C defines a width W1 that is sufficient to support a common tool orimplement, such as the elongate shaft of an ordinary screwdriver, e.g.,a number 2 screwdriver. Preferably, the recess of each fulcrum 20A, 20Band 20C defines a width W1 that is least about ¼ inch to allow insertiontherein of a number 2 screwdriver (which requires a width or clearanceof about 0.27 inch), and preferably is within the range of about ¼ inchto about ⅓ inch. As can be seen, the recessed surface of each fulcrum20A, 20B, and 20C is oriented substantially parallel to the cutting edge14, and is located on the side of the axially-extending aperture or slot18 opposite the cutting edge 14. In addition, each fulcrum 20A, 20B and20C is recessed within the respective side edge of the axially-extendingaperture or slot 18 so that a side edge or lip 21 is formed at eitherend of the fulcrum 20A, 20B and 20C to facilitate retaining a toolwithin the fulcrum 20A, 20B and 20C when levered against it. In theillustrated embodiment, each lip or fulcrum side edge 21 is orientedsubstantially normal to the cutting edge 14 or substantially parallel tothe axis of rotation X of the hole cutter. The illustratedconfiguration, orientation and location of each fulcrum 20A, 20B and 20Cfacilitates engagement of the fulcrum 20A, 20B and 20C by a tool andlevering of the tool against the fulcrum 20A, 20B and 20C to pry orotherwise move a work piece slug out of the interior of the blade body10. Forming at least a portion of the fulcrum surface 20A, 20B and 20Csubstantially parallel to the cutting edge 14, and on the side of theaxially-extending aperture or slot 18 opposite the cutting edge 14,facilitates in levering the tool against the side of the slug oppositethe cutting edge 14 to force the slug out of the interior of the bladebody 10.

As shown in FIG. 1, each slot 18 further defines a side edge 23 that isspaced opposite the fulcrums 20A, 20B and 20C by a minimum width W2 ofthe respective axially-extending slot 18 that is sufficient to allow acommon tool, such as a number 2 screwdriver, to slide axially throughthe axially-extending slot 18 from one fulcrum 20A, 20B or 20C toanother. The minimum width W2 is preferably at least about ¼ inch, ismore preferably within the range of about ¼ inch to about ⅓ inch, and inthe illustrated embodiment, is about 0.27 inch. Also in the illustratedembodiment, the side edge 23 of each axially-extending slot 18 issubstantially smooth and rectilinear to facilitate sliding movement of atool into and through the axially-extending slot 18 (e.g., from onefulcrum 20A, 20B or 20C to another to progressively remove a slug) andto facilitate chip and/or dust egress through the axially-extending slot18. As may be recognized by those of ordinary skill in the pertinent artbased on the teachings herein, the illustrated configuration,orientation, location and dimensions of each fulcrum 20A, 20B and 20Cand axially-elongated aperture or slot 18 are only exemplary, and any ofnumerous other configurations, orientations, locations and/or dimensionsthat are currently known, or that later become known, equally may beemployed.

As shown in FIG. 1, the first fulcrum 20A is axially spaced adjacent tothe cutting edge 14, the second fulcrum 20C is axially spaced furtherfrom the cutting edge 14 as compared to the first fulcrum 20A andadjacent to the rim 16 or non-working end of the hole cutter, and thethird fulcrum 20B is axially spaced between the first and secondfulcrums 20A and 20C. In the illustrated embodiment, the first fulcrum20A is located at approximately one end of the axially-elongatedaperture or slot 18, the second fulcrum 20C is located at approximatelyan opposite end of the aperture or slot 18 relative to the first fulcrum20A, and the third fulcrum 20B is located approximately midway betweenthe first fulcrum 20A and the second fulcrum 20C.

As shown in FIG. 1, the first fulcrum 20A is axially spaced from thecutting edge 14 a first distance D1 within the range of about ½ inch toabout 1 inch, the second fulcrum 20C is angularly spaced relative to thefirst fulcrum 20A and is axially spaced from the cutting edge 14 asecond distance D2 within the range of about 1 ½ inches to about 2inches, and the third fulcrum 20B is angularly and axially spacedbetween the first and second fulcrums 20A and 20C and is axially spacedfrom the cutting edge 14 a third distance D3 within the range of about 1inch to about 1 ½ inches. In the illustrated embodiment, the firstdistance D1 of the first fulcrum 20A is configured for levering slugshaving thicknesses of about ½ inch or less, the third distance D3 of thethird fulcrum 20B is configured for levering slugs having thicknesses ofabout 1 inch or less (e.g., a ¾ inch thick plywood slug), and the seconddistance D2 of the second fulcrum 20C is configured for levering slugshaving thicknesses of about 1 ½ inches or less (e.g., a 2.times.4 slug).In the illustrated embodiment, the distances D1, D2 and D3 are measuredfrom a plane defined by the cutting edge 14, such as a plane extendingbetween the tips of unset teeth. However, as may be recognized by thoseof ordinary skill in the pertinent art based on the teachings herein,the distances between the fulcrums 20A, 20B and 20C and the cutting edge14, or between other features of the hole cutter and the cutting edge14, may be measured with respect to any of numerous other referencelines or features that are currently known or used, or that later becomeknown or used, such as from the base of the deepest gullets of thecutting edge teeth.

In the operation of the hole cutter of FIG. 1, in order to remove, forexample, a relatively thick slug (e.g., a 2.times.4 slug) or a slug thathas traveled deep into the interior of the bade body 10, a user mayinsert a tool through one of the axially-extending slots 18, place thetip of the tool in contact with the side of the slug facing the cap (notshown) or the interior of the blade body 10, select the second fulcrum20C located axially furthest from the cutting edge 14 by placing adistal part of the tool into contact with the fulcrum 20C, and apply aforce to a proximate portion of the tool to use the tool and the fulcrum20C to lever the slug towards the cutting edge 14 and out of theinterior of the blade body 10. If the slug is not removed by leveringthe tool against the second fulcrum 20C, the user can reposition thetool against the third or middle fulcrum 20B that is located axiallycloser to the cutting edge 14 within the same axially-extending slot 18,and use that fulcrum to lever the slug further towards the cutting edge14 and/or out of the interior of the hole cutter. Similarly, if the slugis still not removed from the interior of the blade body 10 by leveringthe tool against the third or middle fulcrum 20B, the user can againreposition the tool, without having to remove the tool from therespective axially-extending slot 18, against the first fulcrum 20Aadjacent to the cutting edge 14, and use the first fulcrum 20A to leverthe slug towards the cutting edge 14 and out of the interior of theblade body 10. As can be seen, each axially-extending slot 18 providesmultiple fulcrums 20A, 20B and 20C that can be used to progressivelylever or otherwise work a slug out of the interior of the blade body 10without having to remove the tool from the respective axially-extendingslot 18.

As shown in FIG. 1, the fulcrums 20A, 20B and 20C are both axially andangularly spaced relative to each other such that the fulcrum 20Aadjacent to the cutting edge 14 is located at a first end 22 of theaxially-extending slot 18 closest to the cutting edge 14, the secondfulcrum 20C is located at an opposite or second end 24 of theaxially-extending slot 18, and the third fulcrum 20B is located betweenthe first and second fulcrums 20A, 20C. In the embodiment of FIG. 1, thediameter of the hole cutter is sufficient to include twoaxially-extending slots 18 oriented at acute angles relative to the axisX of the hole cutter. Accordingly, each axially-extending slot 18 ofFIG. 1 is oriented at an acute angle “A” with respect to the axis X ofthe hole cutter. In the currently preferred embodiments, the angle A isat least about 30 degrees, and is preferably within the range of about35 degrees, to about 60 degrees. In the illustrated embodiment, theacute angle A is about 60 degrees. As can be seen, eachaxially-extending slot 18 slopes away from the cutting edge 14 in adirection opposite the cutting direction of the hole cutter. In thecurrently preferred embodiments of the hole cutters, the first end 22 ofeach axially-extending slot 18 is axially spaced from the cutting edge14 a distance D4 within the range of about 15/100 inch to about ⅜ inch.One advantage of this configuration is that the first or inlet end 22 ofeach axially-extending slot 18 is spaced closely adjacent to the cuttingedge 14 to receive therefrom the chips or dust generated at the cuttingedge 14 and, in turn, allow such chips or dust to egress through theaxially-extending slot 18 and away from the interior of the blade body10. Yet another advantage of this configuration is that the angularorientation of the axially-extending slots 18 facilitates in allowingthe chips to flow up through the axially-extending slots 18 and awayfrom the cutting edge 14 and interior of the blade body 10 as the holecutter is rotated during a cutting operation. A further advantage of theillustrated blade body 10 is that the first or inlet end 22 of eachaxially-extending slot 18 is axially spaced adjacent to the cutting edge14 such that a solid or substantially solid annular portion 26 of theblade body 10 extends between the first or inlet end 22 of eachaxially-extending slot 18 and the cutting edge 14. This annular portion26 of the blade body 10 advantageously provides the blade body 10 withsufficient strength to withstand the heat applied to the blade body 10during the manufacturing of the hole cutter without distorting the bladebody, and provides sufficient strength to the hole cutter to withstandthe forces encountered during cutting operations. However, the annularportion 26 of the blade body 10 is sufficiently thin (as indicatedabove, D4 is within the range of about 15/100 inch to about ⅜ inch) toallow the chips and dust generated at the cutting edge 14 to flow intothe axially-extending slots 18 and away from the interior of the bladebody 10.

In FIGS. 2 and 3, another embodiment of a hole cutter of the presentinvention is indicated generally by the reference numeral 100. The holecutter 100 includes a substantially cylindrical blade body 110 that issubstantially the same as the blade body 10 described above inconnection with FIG. 1, and therefore like reference numerals precededby the numeral “1” are used to indicate like elements. The primarydifference between the blade body 110 of FIGS. 2 and 3 and the bladebody 10 described above is in the shape of the fulcrums 120A, 120B and120C. As can be seen, the fulcrums 120A, 120B and 120C are defined byrecessed curvilinear or radiused edges or surfaces of theaxially-extending slots or apertures 118 that extend angularly in adirection substantially parallel to the cutting edge 114, as opposed torecessed linear edges or surfaces. As shown best in FIG. 3, the radiusedfulcrums 120A, 120B and 120C generally extend angularly in a directionsubstantially perpendicular to the axis of rotation X of the cutter 100,and are curved such that each fulcrum surface 120A, 120B and 120Cinitially extends in a direction away from the cutting edge 114, reachesan apex, and then curves in a direction back towards the cutting edge114. Thus, the radiused fulcrums 120A, 120B and 120C create gullet-likeedges or surfaces wherein the deepest part of each gullet is closest tothe rim 116 or non-working end of the hole cutter 100. In the samemanner as described above in connection with the embodiment of FIG. 1, atool, such as a standard Phillips number 2 screwdriver, can be placedinto contact with the curvilinear fulcrums 120A, 120B and 120C, andpivoted about a respective fulcrum 120A, 120B or 120C to lever a slugout of the interior of the blade body 110. Therefore, the fulcrums 120A,120B and 120C preferably define a radius and/or width W1 sufficient toreceive therein a common tool or implement, such as the elongated shaftof a screwdriver. The width W1 is preferably within the range of about ¼inch to about ⅓ inch. The radiused nature of the fulcrums 120A, 120B and120C is advantageous because the fulcrums 120A, 120B and 120C mimic theshape of common tools, such as the shaft of a screwdriver. In addition,the curvilinear shape of each fulcrum 120A, 120B and 120C laterallysupports a tool received within the 120A, 120B or 120C fulcrum tothereby prevent the tool from slipping, sliding or otherwise becomingdisengaged from the fulcrum 120A, 120B or 120C when levering a workpiece slug. As may be recognized by those of ordinary skill in thepertinent art based on the teachings herein, the above-described fulcrumshapes and dimensions are only exemplary, and any of numerous othershapes and/or dimensions that are currently known, or that later becomeknown, equally may be employed.

Another difference between the blade body 110 of FIGS. 2 and 3 and theblade body 10 described above is the angled orientation of theaxially-extending slots or apertures 118. As shown in FIGS. 2 and 3, theaxially-extending slots or apertures 118 of the blade 110 are set at asmaller acute angle with respect to the axis X of the blade body 110 ascompared to the axially-extending slots or apertures 18 of the blade 10shown in FIG. 1. In the illustrated embodiment shown in FIGS. 2 and 3,the acute angle A is about 47 degrees.

As shown in FIG. 2, the hole cutter 100 includes cap 117 welded to therim 116 of the blade body 110 and forming a part of the non-working endof the hole cutter. The cap 117 includes a central hub 128 defining athreaded aperture for threadedly engaging an arbor, a plurality of drivepin apertures 130 substantially equally spaced relative to each otherabout the central hub 128 for engaging the drive pins of the arbor, anda pair of angularly-extending apertures 132 spaced about 180 degrees,apart on opposite sides of the hub 128 relative to each other. Theangularly-extending apertures 132 are dimensioned and positioned toallow insertion therein of a tool, such as a screwdriver, to furtherfacilitate in work piece slug removal.

In FIG. 4, another embodiment of a hole cutter of the present inventionis indicated generally by the reference numeral 200. The hole cutter 200includes a substantially cylindrical blade body 210 that issubstantially the same as the blade bodies 10 and 110 described above inconnection with FIGS. 1 through 3, and therefore like reference numeralspreceded by the numeral “2”, or preceded by the numeral “2” instead ofthe numeral “1”, are used to indicate like elements. The primarydifference of the blade body 210 in comparison to the blade bodiesdescribed above is that the axially-extending slots or apertures 218 areoriented substantially parallel to the axis of rotation X of the holecutter 200. The blade body 210 forms a relatively small diameter holecutter 200, and therefore the axially-extending slots 218 cannot defineas large a slot area as the larger diameter hole cutters describedabove, and/or cannot be oriented at acute angles relative to the axis ofrotation X of the hole cutter 200. In the illustrated embodiment, theblade body 210 is used to form hole cutters defining blade bodydiameters within the range of about ⅞ inch to about 1 7/16 inches. Thecurrently preferred embodiments of smaller diameter hole cutters (e.g.,about 1 3/16 inches diameter or less) define the same slot configurationas illustrated in FIG. 3, but include only one such slot.

Another difference of the blade body 210 is in the shapes of thefulcrums 220A, 220B and 220C. As can be seen, the first fulcrum 220A isdefined by a curvilinear surface extending laterally from theaxially-extending slot 218 substantially parallel to the cutting edge214, but sloping slightly away from the cutting edge 214 in a directionopposite to the cutting direction of the blade body 210. The firstfulcrum 220A includes only one side edge 221 that is orientedsubstantially parallel to the axis of rotation X of the hole cutter. Thethird or middle fulcrum 220B is similarly defined by a curvilinearsurface extending laterally from the axially-extending slot 218substantially parallel to the cutting edge 214, but sloping slightlyaway from the cutting edge 214 in a direction opposite to the cuttingdirection of the blade body 210. Like the first fulcrum 220A, the thirdor middle fulcrum 220B includes only one side edge 221 that is orientedsubstantially parallel to the axis of rotation X of the hole cutter 200,but is curvilinear rather than rectilinear. The second fulcrum 220C isdefined by the second end 224 of the axially-extending slot 218, and ascan be seen, is defined by a curvilinear surface extending substantiallyparallel to the cutting direction of the blade body 210, and two sidesurfaces 221 extending substantially parallel to the axis of rotation Xof the blade body 210 and formed by the respective side edges of thesecond end 224 of the axially-extending slot 218. In the illustratedembodiment, the width W2 of each of the first fulcrums 220A and thethird or middle fulcrums 220B is preferably within the range of about2/10 to about ½ inch, and more preferable within the range of about ¼ toabout ⅜ inch. The first fulcrums 220A and the third or middle fulcrums220B need not be as wide as the diameter of a number 2 screwdriver, forexample, because part of the screwdriver shaft can be received in thefulcrum 220A, 220B while another portion of the screwdriver shaft canextend into the adjacent portion of the axially-extending slot 218. Thewidth W1 of the third fulcrum 220C, on the other hand, is preferably atleast about 0.27 inches to allow insertion therein of a number 2screwdriver.

Another difference of the hole cutter 200 in comparison to the holecutter 100 described above is the configuration of the first or inletend 222 of each axially-extending slot 218. As can be seen, the sideedge 221 of the first fulcrum 220A extends linearly and substantiallyparallel to the axis of rotation X. The first or inlet end 222 of eachaxially-extending slot 218 is defined by two curvilinear regions. Afirst curvilinear region is contiguous to the first fulcrum side edge221 and defined by one or more relatively small radii R1, and a secondcurvilinear region is contiguous to the side edge 223, is defined by oneor more larger radii R2 and is located on an opposite side of theaxially-extending slot 218 relative to the first fulcrum side edge 221.As can be seen, the larger radius R2 imparts a shape to the respectiveedge of the axially-extending slot 218 that slopes away from the cuttingedge 214 in a direction opposite the cutting direction of the blade body210. In addition, the location of the first fulcrum 220A and theorientation of the respective side edge 221 oriented substantiallyparallel to the axis of rotation X imparts a relatively wide first endor entrance region 222 to the axially-extending slot 218 to facilitatethe flow of chips or dust from the cutting edge 214 into theaxially-extending slot 218. In the illustrated embodiment, the width atthe inlet end 222 of the axially-extending slot 218 is within the rangeof about 1¼ to about 1 ½ times the minimum width W1 or width at theoutlet end 224 of the axially-extending slot 218, and preferably is atleast about 1 ⅓ times the width W1.

In FIG. 5, another embodiment of a hole cutter of the present inventionis indicated generally by the reference numeral 300. The hole cutter 300includes a substantially cylindrical blade body 310 that issubstantially the same as the blade body 210 described above inconnection with FIG. 4, and therefore like reference numerals precededby the numeral “3” instead of the numeral “2”, are used to indicate likeelements. The primary difference of the blade body 310 in comparison tothe blade bodies described in connection with FIG. 4 is that theaxially-extending slots or apertures 318 define two fulcrums 320A, 320Cinstead of three fulcrums. In the illustrated embodiment, the blade body310 is used to form hole cutters defining blade body diameters withinthe range of about ⅞ inch to about 1 7/16 inches. The currentlypreferred embodiments of smaller diameter hole cutters (e.g., about 13/16 inches diameter or less) define the same slot configuration asillustrated in FIG. 5, but include only one such slot. The secondfulcrum 320C is axially spaced from the cutting edge 314 a distance D2within the range of about 1 ½ inches to about 2 inches. As noted above,the second fulcrum 320C being located in this range is advantageouslyconfigured for levering slugs from 2-by wood (e.g., 2.times.4,2.times.6, 2.times.8, etc.), such as slugs of about 1 ⅝ inches or less.

The hole cutters of the present invention may include one or morefeatures of the hole cutters disclosed and/or claimed in any of thefollowing co-pending patent applications that are assigned to theassignee of the present invention and are hereby expressly incorporatedby reference in their entireties as part of the present disclosure: theU.S. patent application filed on even date herewith, U.S. patentapplication Ser. No. 12/687,052, and entitled “Coated Hole Cutter”; theU.S. patent application filed on Jan. 13, 2010, U.S. patent applicationSer. No. 12/687,073, and entitled “Hole Cutter With Minimum Tooth Pitchto Blade Body Thickness Ratio”; the U.S. patent application filed onJan. 13, 2010, U.S. patent application Ser. No. 12/687,102, and entitled“Hole Cutter With Extruded Cap”; the U.S. patent application filed onJan. 13, 2010, U.S. patent application Ser. No. 12/687,078, and entitled“Hole Cutter With Chip Egress Aperture”; the U.S. Design patentapplication filed on Jan. 13, 2010, U.S. patent application Ser. No.29/353,762, and entitled “Hole Saw”; and the U.S. Design patentapplication filed on Jan. 13, 2010, U.S. patent application Ser. No.29/353,759, and entitled “Hole Saw”.

It may be readily understood by those having skill in the pertinent artfrom the present disclosure that any of numerous changes andmodifications may be made to the above-described and other embodimentsof the present invention without departing from the scope of theinvention as defined in the appended claims. For example, the holecutters may be made from any of numerous different materials, in any ofnumerous shapes, taking any of numerous different dimensions. Forexample the cutting edge may be made from any of numerous differentmaterials or combinations of materials that are currently known or thatlater become known. As an example, the cutting edge may take any form,pattern, arrangement or configuration that is currently known or thatlater becomes known, including without limitation, tooth patterns thattend to function well in specific applications, hybrid applications orgeneral applications. For example, the cutting teeth may define any ofnumerous different tooth forms, pitch patterns and/or set patterns. Asanother example, a single aperture may be provided in the body of thecutter, two or more apertures may be angularly and/or axially alignedwith one another, or two or more apertures may be variably angularlyand/or axially spaced relative to one another. Also, the hole cuttersmay be used in any of numerous different cutting applications, on any ofnumerous different work piece materials, such as woods, metals,plastics, composites, resins, stones, fabrics, foams, etc. Further, oneor more apertures may extend to the cutting edge, to the rim of the sidewall or cap, or even extend to both the cutting edge and to the rim ofthe side wall or cap. As another example, the length or width of eachfulcrum may not be the same from fulcrum to fulcrum or aperture toaperture. As yet another example, the fulcrum surfaces may not extendlinearly in a direction perpendicular to the axis of rotation of thecutter about the circumference of the cutter. Instead, the fulcrumsurfaces may define curved, curvilinear, rectilinear, angled surfacesand/or combinations of the foregoing. Still further, the aperture sideedges may not extend linearly and axially to define the angular width ofthe angled slots or apertures and connect the outer-lying fulcrums tothe bottom edge surface of the apertures by radiused corners. Instead,for example, the aperture side edges may be curved, curvilinear,rectilinear, angled and/or any combination of the foregoing, and theintersections of the aperture side edges and the end surfaces of theapertures and the outer-lying fulcrums may be right, obtuse and/or acuteintersections, or may define rectilinear and/or curvilinear corners.Similarly, the surfaces that extend between the fulcrums may not belinear and the transitions between the surfaces may not be defined byradiuses. As an alternative, for example, these surfaces may be curved,curvilinear, rectilinear and/or alternatively angled, and thetransitions between these surfaces may be right, obtuse and/or acuteintersections or may define curvilinear and/or rectilinear corners. Asanother example, additional surfaces may be included, or surfaces may beremoved, from the apertures, such as surfaces located adjacent to, orbetween, the fulcrums. In addition, the axially-elongated apertures orslots may define a different number of fulcrums or like surfaces thanillustrated herein, or some axially-elongated apertures or slots maydefine a different number for type of fulcrums than other apertures orslots of the same hole cutter. Accordingly, this detailed description ofthe currently preferred embodiments of the present invention is to betaken in an illustrative, as opposed to a limiting sense.

What is claimed is:
 1. A hole cutter comprising: a substantiallycylindrical blade body having a smooth outer wall, the blade bodydefining a cutting edge and a longitudinal axis; a first apertureportion formed through the blade body and spaced from the cutting edgesuch that a portion of the blade body extends between the cutting edgeand the first aperture portion, the first aperture portion configured toreceive therethrough a lever for removing a work piece slug from aninterior of the blade body and defining a first fulcrum configured forengaging the lever and for levering the slug out of the interior of theblade body by applying a sufficient levering force against the firstfulcrum to lever the slug towards the cutting edge; a second apertureportion formed through the blade body and spaced from the cutting edgesuch that a portion of the blade body extends between the cutting edgeand the second aperture portion, the second aperture portion configuredto receive therethrough a lever for removing a work piece slug from aninterior of the blade body and defining a second fulcrum configured forengaging the lever and for levering the slug out of the interior of theblade body by applying a sufficient levering force against the secondfulcrum to lever the slug towards the cutting edge; wherein the firstfulcrum is axially spaced from the cutting edge a first distance, thesecond fulcrum is axially spaced from the cutting edge a second distancethat is greater than the first distance, wherein the first fulcrum isdefined by a first top edge of the first aperture portion, wherein thefirst top edge comprises a substantially straight edge that issubstantially parallel to the cutting edge, wherein at least a portionof the first aperture portion and at least a portion of the secondaperture portion are aligned along a line substantially parallel to thelongitudinal axis and the first fulcrum and the second fulcrum arealigned along the line substantially parallel to the longitudinal axis,and wherein at least one of the first aperture portion and the secondaperture portion is bounded by a bottom edge axially spaced a thirddistance from the cutting edge, a top edge spaced a fourth distance fromthe cutting edge greater than the third distance, and a side edgeconnecting the bottom edge to the top edge and oriented at an acuteangle to the longitudinal axis of the blade body.
 2. The hole cutter ofclaim 1, wherein the first aperture portion is in communication with thesecond aperture portion via a slot portion.
 3. The hole cutter of claim1, wherein the first fulcrum is defined by a first bottom edge of thefirst aperture portion wherein the first bottom edge is a substantiallystraight edge that is substantially parallel to the cutting edge.
 4. Thehole cutter of claim 3, wherein the first top edge is substantiallyparallel to the first bottom edge and is spaced from the cutting edge.5. The hole cutter of claim 4, wherein the second aperture portionincludes a second top edge, wherein the second top edge is asubstantially straight edge that is substantially parallel to thecutting edge and that defines the second fulcrum and a second bottomedge that is a substantially straight edge that is substantiallyparallel to the second top edge and that is spaced from the cuttingedge.
 6. The hole cutter of claim 1, wherein the second fulcrum isdefined by a second top edge of the second aperture portion wherein thesecond top edge is a substantially straight edge that is substantiallyparallel to the cutting edge.
 7. The hole cutter of claim 1, whereineach of the first aperture portion and the second aperture portiondefines a minimum width of about 0.27 inch to allow insertion of anumber 2 screwdriver therethrough.
 8. The hole cutter of claim 1,wherein the second aperture portion is axially elongated.
 9. The holecutter of claim 1, wherein the first and second fulcrums are defined byfirst and second edges of the first and second apertures that arecurved, curvilinear, rectilinear, or a combination thereof.
 10. The holecutter of claim 1, wherein the first top edge comprises: a substantiallystraight edge comprising a first end and a distal second end; a firstcurved corner at the first end; and a second curved corner at the secondend.
 11. The hole cutter of claim 1, wherein the cutting edge comprisesa plurality of teeth disposed continuously around a circumference of thecutting edge.
 12. The hole cutter of claim 1, wherein an other one ofthe first aperture portion and the second aperture portion comprises asecond side edge oriented at the acute angle to the longitudinal axis,wherein the second side edge is collinear with the first side edge. 13.A hole cutter comprising: a substantially cylindrical blade bodydefining a longitudinal axis and a cutting edge comprising a pluralityof teeth disposed continuously around a circumference of the cuttingedge; a first aperture portion formed through the blade body and spacedfrom the cutting edge such that a portion of the blade body extendsbetween the cutting edge and the first aperture portion, the firstaperture portion configured to receive therethrough a lever for removinga work piece slug from an interior of the blade body and defining afirst fulcrum configured for engaging the lever and for levering theslug out of the interior of the blade body by applying a sufficientlevering force against the first fulcrum to lever the slug towards thecutting edge; a second aperture portion formed through the blade bodyand spaced from the cutting edge such that a portion of the blade bodyextends between the cutting edge and the second aperture portion, thesecond aperture portion configured to receive therethrough a lever forremoving a work piece slug from an interior of the blade body anddefining a second fulcrum configured for engaging the lever and forlevering the slug out of the interior of the blade body by applying asufficient levering force against the second fulcrum to lever the slugtowards the cutting edge; wherein the first fulcrum is axially spacedfrom the cutting edge a first distance, the second fulcrum is axiallyspaced from the cutting edge a second distance that is greater than thefirst distance, wherein the first fulcrum is defined by a first top edgeof the first aperture portion, wherein the first top edge comprises asubstantially straight edge that is substantially parallel to thecutting edge, wherein at least a portion of the first aperture portionand at least a portion of the second aperture portion are aligned alonga line substantially parallel to the longitudinal axis and wherein thefirst fulcrum and the second fulcrum are aligned along the line that issubstantially parallel to the longitudinal axis, wherein at least one ofthe first aperture portion and the second aperture portion is bounded bya bottom edge axially spaced a third distance from the cutting edge, atop edge spaced a fourth distance from the cutting edge greater than thethird distance, and a first side edge connecting the bottom edge to thetop edge and oriented at an acute angle to the longitudinal axis of theblade body, and wherein an other one of the first aperture portion andthe second aperture portion comprises a second side edge oriented at theacute angle to the longitudinal axis, wherein the second side edge iscollinear with the first side edge.
 14. The hole cutter of claim 13,wherein the second fulcrum is angularly spaced around a circumference ofthe blade body relative to the first fulcrum.
 15. The hole cutter ofclaim 13, wherein the second fulcrum is defined by a second top edge ofthe second aperture portion wherein the second top edge is asubstantially straight edge that is substantially parallel to thecutting edge.
 16. The hole cutter of claim 13, wherein the firstaperture portion is in communication with the second aperture portionvia a slot portion.